WASHINGTON, Aug. 12 (Xinhua) -- U.S. authorities have concluded that Taliban in Afghanistan is far less relied on drug money than widely estimated, but drug trade remains critical to its survival, according to a congressional study.

    The document, revealed by the Military Times and other U.S. news outlets Wednesday, said U.S. spy agencies now believe that Taliban receives about 70 million U.S. dollars a year from Afghanistan's lucrative poppy crop -- far lower than the 400 million dollars estimated by the United Nations Office of Drugs and Crime.

    For Al-Qaida operatives in Afghanistan, their dependence on drug money is even less, according to the report.

    The study suggests that other avenues of funding -- including money flowing from wealthy donors in Arab Gulf states -- remain important sources of support for insurgent and terrorist networks straddling the border between Afghanistan and Pakistan.

    The report came at a time when the United States is revamping its approach to combating the lucrative narcotics trade in Afghanistan, whose poppy fields account for more than 90 percent of the world's heroin.